Plant matter, such as cannabis, contains active chemicals that are useful for medicinal purposes to treat disease or alleviate symptoms. The active chemicals can be can be utilized in natural form in the plant matter, e.g., by smoking. Alternatively, the active chemicals can be extracted and isolated for use, for scientific study, or for other purposes. Extraction techniques, however, are inefficient. The amount of plant matter that can be processed at one time is limited, and only a small fraction of the active chemicals present are extracted.